Metal fixtures, components and parts are commonly manufactured from metal alloys that contain various amounts of lead. These fixtures are often used in plumbing applications. Such applications include parts for water flow fixtures such as faucets, spouts, shower heads, plumbing pipes, pipe fittings, shut-off valves, water meters, pressure and flow regulators, ice makers, and the like.
In 1991 the National Primary Drinking Water Regulations established an action level of 15 ppb of lead in drinking water. In 1996 the Safe Water Drinking Act amendments reduced the allowable amount of lead in brass used for potable water supply systems to 8%. These regulations set forth limits for the maximum quantity of lead that is permitted to be leached into potable water systems from plumbing fixtures and other delivery components during periods of use and non-use. The United States Environmental Protection Agency (EPA) designated the National Sanitation Foundation (NSF) as the organization to establish the testing standards to meet the federal regulations. Those standards are now known as the NSF-61 standard. Numerous municipalities, counties, states, and other governing bodies now require compliance with the NSF-61 standard for products supplied for use in potable water delivery systems within their jurisdictions.
Many metal fixtures, components and parts do not meet the NSF standards at the time of manufacturing. Methods have been developed to treat the metal fixtures to remove lead from the surface of the plumbing fixtures, components and parts so that they meet the NSF standards and are thus safe to use in municipal and residential water supplies. Several problems and disadvantages are associated with the current methods for removing lead from metal fixtures. These problems and disadvantages include large amounts of toxic or undesirable waste products including caustic solutions, processing difficulties including multi-step procedures, the high costs associated with multi-step procedures, relatively high operating temperatures in some cases, and treating compositions that tarnish the metals.
Accordingly, what is needed are compositions and methods that can remove lead from metal surfaces with fewer problems and disadvantages than are associated with current compositions and methods. Such a composition would result in fewer undesirable waste products and would be less expensive to manufacture. The methods of treating the metal would require fewer steps and/or simpler procedures, lower operating temperatures, and thus lower costs to employ the methods.